The White House on Thursday stood by President Donald Trump's unproven accusations that his predecessor wiretapped his New York skyscraper, despite growing bipartisan agreement that there's no evidence to back up the claim and mounting pressure to retract the statement.

Angrily defending the president's statement, White House spokesman Sean Spicer told reporters Trump "stands by" the four tweets that sparked a firestorm that has threatened Trump's credibility with lawmakers.